This project is concerned with the identification and characterization of components of the lung associated with pulmonary diseases which could provide information concerning the disease processes as well as function as diagnostic markers of pulmonary damage or disease. Current attention has been focused on the protein components of the acellular lining of the normal human lung and the lungs of patients with pulmonary alveolar proteinosis. The objectives are to identify and enumerate the protein constituents in the acellular lining of the normal lung and thus provide a baseline against which disease and lung damage may be measured.